Communications system, communications method, network manager, and transfer device

ABSTRACT

A communications system which allows data transfer not using a terminal ID assigned by an access network but using routing information distinct from the terminal ID is provided. The communications system transmits data including, as a destination address, a second terminal ID, from a first terminal to the second terminal via a plurality of transfer devices. A first transfer device includes a first memory for storing the second terminal ID and routing information for routing the data to a second transfer device, associating them with one another, and a routing processor for adding to the data the routing information for routing the data to the second transfer device associated with the second terminal ID included in the data, and transferring the data to the second transfer device.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. P2002-056474, filed onMar. 1, 2002; the entire contents of which are incorporated herein byreference

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a communications system and acommunications method for transmitting data including, as a destinationaddress, a second terminal ID (information identifying the secondterminal), from a first terminal to the second terminal via a pluralityof transfer devices, and a transfer device and a network managersuitable for use therein.

[0004] 2. Description of the Related Art

[0005] In a conventional communications system, a terminal moving withina communications network uses address information assigned by an accessnetwork with which the terminal has newly established connection at anew location, for communications. A given address information piece isassigned to the terminal from among address information pieces assignedto an access network to which the terminal is physically connected.

[0006] The conventional communications system, however, has a problem inthat when the terminal conducts communications using the assignedaddress information, the party on the other end of the connection candetect from the address information the access network to which theabove terminal is physically connected. That is, in such a case, thelocation information of the user can be problematically leaked to theparty on the other end.

[0007] As an art designed to provide packet transmitting and receivingfunctions to a terminal moving within a communications network under thesame setting environment, “Mobile IP” is known.

[0008] Under “Mobile IP,” in order to prevent the leakage of thelocation information of the user, the terminal always transmits to theparty on the other end, data with a “home address” assigned by a “homeagent” of a “home network” set as the source address. The party on theother end always transmits data provided with the “home address” to theterminal, assuming that the terminal is located in the “home network.”As a result, the data transmitted from the party on the other end isalways transferred to the “home network (home agent)” of the terminaland then transferred from the “home network” to a network to which theterminal is connected at that time.

[0009] The conventional communications system using “Mobile IP,”however, has a problem in that the terminal needs to perform complicatedsettings so as to specify information for transfer to the terminal, forthe “home agent.”

[0010] The conventional communications system using “Mobile IP” hasanother problem in view of a data transfer path in which datatransferred must pass through a relay point (home agent) constituting atriangular path.

[0011] The conventional communications system using “Mobile IP” has yetanother problem in that the terminal needs to perform highly functionalprocessing. The terminal needs, for example, to hold both the addressinformation assigned by an access network to which the terminal isconnected, and the home address of the terminal, and to perform suchprocessing as releasing the encapsulation of packets received.

[0012] The conventional communications system using “Mobile IP” hasstill another problem in that it is required to transmit and receivepackets in a format which includes an information element constitutingan overhead, even in a radio section between the terminal and an accesspoint in the access network.

[0013] The conventional communications system using “Mobile IP” hasstill another problem in that it is based on “end-to-end data transfer”,a basic principle of the internet protocol, and the terminal needs tospecify, as transfer information, both a terminal ID and routinginformation (that is, address information assigned by an access networkand a terminal home address) for data transfer.

[0014] The conventional communications system using “Mobile IP” hasstill another problem in that path-to-path processing, routingprocessing, or the like, results in a transmission mode includingredundant path information.

[0015] The conventional communications system using “Mobile IP” hasstill another problem in that since bandwidth control is performed byencapsulation using MPLS or the like, the party on the other end candetect the location information of the terminal from address informationassigned by an access network.

BRIEF SUMMARY OF THE INVENTION

[0016] The present invention has been made in view of the above and hasan object of providing a communications system and a communicationsmethod which allow data transfer not using a terminal ID assigned by anaccess network but using routing information distinct from the terminalID, and a transfer device and a network manager suitable for usetherein.

[0017] According to the present invention, there is provided acommunications system for transmitting data including, as a destinationaddress, a second terminal ID (information identifying a secondterminal), from a first terminal to the second terminal via a pluralityof transfer devices, the system comprising: a first transfer deviceconnected to the first terminal, the first transfer device comprising: afirst memory configured to store the second terminal ID and routinginformation for routing the data to a second transfer device connectedto the second terminal, associating them with one another; and a routingprocessor configured to add to the data the routing informationassociated with the second terminal ID included in the data receivedfrom the first terminal, and to transfer the data to the second transferdevice.

[0018] The communications system preferably further comprises a networkmanager, the network manager comprising: a second memory configured tostore the second terminal ID and the routing information for routing thedata to the second transfer device, associating them with one another;and an instruction information transmitter configured to transmitinstruction information including the routing information for routingthe data to the second transfer device associated with the secondterminal ID, in response to a transfer request including the secondterminal ID transmitted from the first transfer device; wherein, thefirst transfer device comprises a transfer request transmitterconfigured to transmit the transfer request to the network manager uponreceiving a transmission request for the data from the first terminal;and the first memory stores the second terminal ID and the routinginformation for routing the data to the second transfer device,associating them with one another, according to the instructioninformation from the network manager.

[0019] The instruction information transmitter preferably transmits theinstruction information to the second transfer device. The first memorypreferably stores the second terminal ID and the routing information forrouting the data to the second transfer device, associating them withone another, according to the instruction information received via thesecond transfer device.

[0020] The data transmission request preferably includes controlinformation on the transmission of the data from the first terminal tothe second terminal. The first memory preferably stores the secondterminal ID, the routing information for routing the data to the secondtransfer device and the control information, associating them with oneanother. The routing processor preferably transfers the data to thesecond transfer device, based on the control information.

[0021] The first memory alternatively stores a first terminal ID(information identifying the first terminal), the second terminal ID,the routing information for routing the data to the second transferdevice and a communication ID element, associating them with oneanother. The routing processor preferably adds to the data the routinginformation associated with the communication ID element included in thedata received from the first terminal, and transfers the data to thesecond transfer device.

[0022] The network manager alternatively comprises a third memoryconfigured to store the first terminal ID, the second terminal ID, therouting information for routing the data to the second transfer deviceand the communication ID element, associating them with one another; andan instruction information transmitter configured to transmitinstruction information including the routing information and thecommunication ID element associated with the first terminal ID and thesecond terminal ID, in response to a transfer request including thefirst terminal ID and the second terminal ID transmitted from the firsttransfer device. The first transfer device preferably comprises atransfer request transmitter configured to transmit the transfer requestto the network manager upon receiving a transmission request for thedata from the first terminal. The first memory preferably stores thefirst terminal ID, the second terminal ID, the routing information forrouting the data to the second transfer device and the communication IDelement, associating them with one another, according to the instructioninformation from the network manager.

[0023] According to the present invention, there is provided acommunications method of transmitting data including, as a destinationaddress, a second terminal ID, from a first terminal to the secondterminal via a plurality of transfer devices, the method comprising thestep of: A) adding to the data, at a first transfer device which isconnected to the first terminal and stores the second terminal ID androuting information for routing the data to a second transfer device towhich the second terminal is connected, associating them with oneanother, the routing information associated with the second terminalincluded in the data, and transferring the data to the second transferdevice.

[0024] The communications method preferably further comprises the stepsof: B) transmitting, at the first transfer device, a transfer requestincluding the second terminal ID to a network manager upon receiving atransmission request for the data from the first terminal; C)transmitting, at the network manager, instruction information includingthe routing information associated with the second terminal ID, inresponse to the transfer request transmitted from the first transferdevice; and D) storing, at the first transfer device, the secondterminal ID and the routing information for routing the data to thesecond transfer device, associating them with one another, according tothe instruction information from the network manager.

[0025] In step C), the network manager preferably transmits theinstruction information to the second transfer device; and in step D),the first transfer device preferably stores the second terminal ID andthe routing information for routing the data to the second transferdevice, associating them with one another, according to the instructioninformation received via the second transfer device.

[0026] In step B), the data transmission request preferably includescontrol information on the transmission of the data from the firstterminal to the second terminal; the first transfer device preferablystores the second terminal ID, the routing information for routing thedata to the second transfer device and the control information,associating them with one another; and in step A), the first transferdevice preferably transfers the data to the second transfer device basedon the control information.

[0027] The first transfer device alternatively stores the first terminalID, the second terminal ID, the routing information for routing the datato the second transfer device and a communication ID element,associating them with one another; and in step A), the first transferdevice adds to the data the routing information associated with thecommunication ID element included in the data received from the firstterminal, and transfers the data to the second transfer device.

[0028] The communications method preferably further comprises the stepsof: E) transmitting, at the first transfer device, a transfer requestincluding the first terminal ID and the second terminal ID to a networkmanager upon receiving a transmission request for the data from thefirst terminal, the network manager storing the first terminal ID, thesecond terminal ID, the routing information for routing the data to thesecond transfer device and the communication ID information element,associating them with one another; F) transmitting, at the networkmanager, instruction information including the routing information andthe communication ID element associated with the first terminal ID andthe second terminal ID, in response to the transfer request transmittedfrom the first transfer device; and G) storing, at the first transferdevice, the first terminal ID, the second terminal ID, the routinginformation for routing the data to the second transfer device and thecommunication ID element, associating them with one another, accordingto the instruction information from the network manager.

[0029] According to the invention, there is provided a first transferdevice connected to a first terminal for transmitting data including, asa destination address, a second terminal ID, from the first terminal tothe second terminal, the first transfer device comprising: a firstmemory configured to store the second terminal ID and routinginformation for routing the data to a second transfer device to whichthe second terminal is connected, associating them with one another; anda routing processor configured to add to the data the routinginformation associated with the second terminal ID included in the data,and to transfer the data to the second transfer device.

[0030] The first transfer device preferably further comprises: atransfer request transmitter configured to transmit a transfer requestincluding the second terminal ID to a network manager upon receiving atransmission request for the data from the first terminal; wherein, thefirst memory stores the second terminal ID and the routing informationfor routing the data to the second transfer device, associating themwith one another, upon receiving instruction information including therouting information associated with the second terminal ID from thenetwork manager.

[0031] The first memory alternatively stores a first terminal ID, thesecond terminal ID, the routing information for routing the data to thesecond transfer device and a communication ID element, associating themwith one another; and the routing processor adds to the data the routinginformation associated with the communication ID element included in thedata received from the first terminal, and transfers the data to thesecond transfer device.

[0032] The first transfer device further comprises a transfer requesttransmitter configured to transmit a transfer request including thefirst terminal ID and the second terminal ID to a network manager uponreceiving a transmission request for the data from the first terminal.The first memory stores the first terminal ID and the second terminalID, the routing information for routing the data to the second transferdevice and the communication ID element, associating them with oneanother, according to instruction information from the network manager.

[0033] According to the invention, there is provided a network managerfor managing a communications system for transmitting data including, asa destination address, a second terminal ID, from a first terminal tothe second terminal via a plurality of transfer devices, the networkmanager comprising: a second memory storing the second terminal ID androuting information for routing the data to a second transfer device towhich the second terminal is connected, associating them with oneanother; and an instruction information transmitter configured totransmit instruction information including the routing informationassociated with the second terminal ID, in response to a transferrequest including the second terminal ID transmitted from a firsttransfer device to which the first terminal is connected.

[0034] According to the invention, there is provided a network managerfor managing a communications system for transmitting data including asecond terminal ID as a destination address and including a firstterminal ID as a source address, from the first terminal to the secondterminal via a plurality of transfer devices, the network managercomprising: a third memory configured to store the first terminal ID,the second terminal TD routing information for routing the data to asecond transfer device to which the second terminal is connected and acommunication ID element, associating them with one another; and aninstruction information transmitter configured to transmit instructioninformation including the routing information for routing the data tothe second transfer device to which the second terminal is connected andthe communication ID element associated with the first terminal ID andthe second terminal ID, in response to a transfer request including thefirst terminal ID and the second terminal ID transmitted from a firsttransfer device.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0035]FIG. 1 is a diagram of the entire configuration of acommunications system according to a first embodiment of the presentinvention;

[0036]FIG. 2 is a functional block diagram of a network manageraccording to the first embodiment of the present invention;

[0037]FIG. 3 is a functional block diagram of a transfer deviceaccording to the first embodiment of the present invention;

[0038]FIG. 4 is a diagram exemplifying the configuration of a terminalID-routing information-control information associating unit of thetransfer device according to the first embodiment of the presentinvention;

[0039]FIG. 5 is a sequence diagram illustrating the operation of thecommunications system according to the first embodiment of the presentinvention;

[0040]FIGS. 6A and 6B are diagrams exemplifying formats of datatransferred in the communications system according to the firstembodiment of the present invention;

[0041]FIGS. 7A and 7B are diagrams exemplifying the configuration of aterminal ID-routing information-control information associating unit ofa transfer device according to a second embodiment of the presentinvention;

[0042]FIG. 8 is a sequence diagram illustrating the operation of acommunications system according to the second embodiment of the presentinvention;

[0043]FIGS. 9A to 9C are diagrams exemplifying formats of datatransferred in the communications system according to the secondembodiment of the present invention;

[0044]FIG. 10 is a sequence diagram illustrating the operation of acommunications system according to a third embodiment of the presentinvention;

[0045]FIGS. 11A and 11B are diagrams exemplifying formats of datatransferred in a communications system according to a modification ofthe present invention; and

[0046]FIG. 12 is a diagram exemplifying the configuration of a terminalID-routing information-control information associating unit of atransfer device according to the modification of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0047] (Configuration of a Communications System in Embodiment 1)

[0048] The configuration of a communications system according to a firstembodiment of the present invention will be described with reference toFIGS. 1 to 3. FIG. 1 illustrates the entire configuration of thecommunications system of this embodiment.

[0049] The communications system of this embodiment transmits dataincluding information identifying a second terminal 51 (hereinafterreferred to as an ID-terminal 51) as the destination address andincluding information identifying a first terminal 52 (hereinafterreferred to as an ID-terminal 52) as the source address, from the firstterminal 52 to the second terminal 51 via a plurality of transferdevices 30 ₁, 30 ₃, 20 ₃ and 20 ₁, as shown in FIG. 1.

[0050] The first terminal 51 and the second terminal 52 can move insubnetworks (access networks) 2 and 3 constituting a network 1, beingconnected to the transfer devices (access points) 30 ₁, and 20 ₁, forexample, in the subnetworks 2 and 3 in a wireless or wired system. Thisembodiment will be described with the first terminal 51 and the secondterminal 52 wirelessly connected to the transfer devices (access points)30 ₁ and 20 ₁, for example, in the subnetworks 2 and 3.

[0051] The “ID-terminal 51” and “ID-terminal 52” may be any addressinformation such as IP addresses assigned to the first terminal 52 andthe second terminal 51, respectively.

[0052] The communications system of this embodiment includes a networkmanager 10 and a plurality of transfer devices 20 ₁, to 20 ₃ and 30 ₁,to 30 ₃, as shown in FIG. 1.

[0053] The network manager 10 manages the communications system (network1) of this embodiment. More specifically, the network manager 10includes, as shown in FIG. 2, a transfer request receiver 11, a terminalID-location information associating unit 12, a locationinformation-transfer device ID associating unit 13, and a routinginformation setting instructing unit 14.

[0054] The transfer request receiver 11 is connected to the routinginformation setting instructing unit 14. The receiver 11 receives a“transfer request” including the “the second terminal ID (destinationterminal ID, ID-terminal 51)” transmitted from the first transfer device30 ₁ to which the first terminal 52 is connected, and transmits thereceived transfer request to the routing information setting instructingunit 14. The transfer request may include control information forcontrolling a communication bandwidth or the like (e.g., 64 Kbps).

[0055] The terminal ID-location information associating unit 12 isconnected to the routing information setting instructing unit 14. Theunit 12 stores “terminal IDs” of terminals located in the network 1 andassociated “location information” of the terminals.

[0056] The location information-transfer device ID associating unit 13is connected to the routing information setting instructing unit 14. Theunit 13 stores “transfer device IDs” and associated “locationinformation” of the terminals which can be connected to the transferdevices.

[0057] When the first terminal 51 and the second terminal 52 areconnected to the transfer devices (access points) 30 ₁ and 20 ₁, forexample, in the subnetworks 2 and 3 in a wired system, the terminalID-location information associating unit 12 and the locationinformation-transfer device ID associating unit 13 may be united toassociate the “terminal IDs” with the “transfer device IDs” to which theterminals are connected.

[0058] The routing information setting instructing unit 14 is connectedto the transfer request receiver 11, the terminal ID-locationinformation associating unit 12 and the location information-transferdevice ID associating unit 13. The routing information settinginstructing unit 14 constitutes an instruction information transmitterfor transmitting, in response to a transfer request transmitted throughthe transfer request receiver 11, a “routing information settinginstruction (instruction information)” including the “destinationtransfer device ID (routing information for routing the data to thesecond transfer device 201)” associated with the “second terminal ID(ID-terminal 51).” The “routing information setting instruction caninclude a terminal ID identifying a terminal connected to thedestination transfer device, instead of the destination transfer deviceID.

[0059] The “routing information setting instruction (instructioninformation)” may include control information included in the transferrequest.

[0060] More specifically, the routing information setting instructingunit 14 searches the terminal ID-location information associating unit12 and the location information-transfer device ID associating unit 13,with the “second terminal ID (ID-terminal 51)” included in the transferrequest as a keyword, thereby obtaining the “information identifying thesecond transfer device 20 ₁ (routing information for routing the data tothe second transfer device 20 ₁)” associated with the “second terminalID (ID-terminal 51),” and transmits to each of the plurality of transferdevices 20 ₃, 30 ₁ and 30 ₃ a “routing information setting instruction(instruction information)” including the “information identifying thesecond transfer device 20 ₁, (RA-20 ₁)” and “transfer information (RA-30₃).”

[0061] The routing information setting instructing unit 14 may transmitthe “routing information setting instruction (instruction information)”to all transfer devices located in the network 1.

[0062] In this embodiment, the routing information setting instructingunit 14 constitutes a second memory which stores the “second terminal ID(ID-terminal 51)” and the “second transfer device ID, that is, therouting information for routing the data to the second transfer device(e.g., RA-20 ₁, for the transfer device 30 ₁),” associating them withone another. The routing information can be a terminal ID identifying aterminal connected to the transfer device 30 ₁, instead of RA-20 ₁.

[0063] The memory contents of the second memory may be set by a networkadministrator or may be dynamically obtained by the network manager 10from a transfer device in a specified area upon the transfer request.

[0064] The plurality of transfer devices 20 and 30 cooperativelytransfer from the first terminal 52 to the second terminal 51 the dataincluding the “second terminal ID (ID-terminal 51)” as the destinationaddress and the “first terminal ID (ID-terminal 52)” as the sourceaddress.

[0065] More specifically, the transfer devices 20 and 30 each include,as shown in FIG. 3, a receiver 21, a transfer request transmitter 22, arouting information setting instruction receiver 23, a terminalID-routing information-control information associating unit 24, arouting processor 25, and a transmitter 26. Description will be madebelow with the first transfer device 30 ₁, to which the first terminal52 is connected.

[0066] The receiver 21 is connected to the transfer request transmitter22, terminal ID-routing information-control information associating unit24 and routing processsor 25. The receiver 21 receives data transmittedfrom the first terminal 52 and transfers the received data to therouting processor 25.

[0067] When receiving only data including a data transmission request ora data transmission request from the first terminal 52, the receiver 21searches, in response to the data transmission request, the terminalID-routing information-control information associating unit 24 for arecord including the “second terminal ID” included in the data (or datatransmission request).

[0068] When the terminal ID-routing information-control informationassociating unit 24 includes the record, the receiver 21 transfers tothe routing processor 25 the data including the data transmissionrequest or data transmitted subsequently to the data transmissionrequest.

[0069] When the terminal ID-routing information-control informationassociating unit 24 does not include the record, the receiver 21transfers the data transmission request including the “second terminalID” to the transfer request transmitter 22.

[0070] The data transmission request includes, for example, the “firstterminal ID (ID-terminal 52)” as the source address, the “secondterminal ID (ID-terminal 51)” as the destination address, and controlinformation for controlling the communication bandwidth or the like(e.g., 64 Kbps). When it is desired to change the condition ofcommunications with the second terminal 51, the first terminal 52transmits data transmission request including the control information tothe transfer device 30 ₁.

[0071] The transfer request transmitter 22 is connected to the receiver21. In response to the “data transmission request” transmitted throughthe receiver 21, the transmitter 22 transmits a transfer requestincluding the “second terminal ID (ID-terminal 51)” and the “controlinformation (e.g., 64 Kbps)” to the network manager 10.

[0072] The routing information setting instruction receiver 23 isconnected to the terminal ID-routing information-control informationassociating unit 24. The receiver 23 receives a “routing informationsetting instruction (instruction information)” transmitted from thenetwork manager 10 and updates the memory contents of the terminalID-routing information-control information associating unit 24 accordingto the received “routing information setting instruction (instructioninformation).”

[0073] The terminal ID-routing information-control informationassociating unit 24 is connected to the routing information settinginstruction receiver 23 and the routing processor 25. The unit 24constitutes a first memory storing “IDs of destination terminals(destination terminal IDs),” “IDs of transfer devices (destinationtransfer device IDs) to which the destination terminals are connected,”“transfer information” for the transfer of the received data, and the“control information” for the transmission of data to the transferdevices, associating them with one another.

[0074]FIG. 4 illustrates an example of the memory contents of theterminal ID-routing information-control information associating unit 24of the first transfer device 30 ₁. In the example of FIG. 4, theterminal ID-routing information-control the “destination terminalID=ID-terminal 51 (information identifying the second terminal 51,second terminal ID),” the “destination transfer device ID=RA-20 ₁(information identifying the second transfer device 20 ₁),” the“transfer information=RA-30 ₃ (information identifying the transferdevice 30 ₃)” and the “control information=64 Kbps,” and a second recordincluding the “destination terminal ID=ID-terminal 52 (informationidentifying the first terminal 51, first terminal ID),” the “destinationtransfer device ID=RA-30 ₁ (information identifying the first transferdevice 30 ₁),” the “transfer information=Wireless (wireless connection)”and the “control information=none.” The second record shows that thefirst terminal 52 is wirelessly connected to the first transfer device30 ₁.

[0075] The routing processor 25 is connected to the receiver 21, theterminal ID-routing information-control information associating unit 24and the transmitter 26. The routing processor 25 adds to the data the“routing information for routing the data to the destination transferdevice 20 ₁, (ID RA-20 ₁ of the second transfer device 20 ₁)” associatedwith the “second terminal ID (ID-terminal 51)” included in the datatransmitted via the receiver 21 from the first terminal 52, andtransfers the data via the transmitter 26 to the transfer device 30 ₃based on the “control information (e.g., 64 Kbps)” associated with the“second terminal ID (ID-terminal 51).”

[0076] The transmitter 26 is connected to the routing processor 25. Thetransmitter 26 transfers the data transmitted from the routing processor25 to the second transfer device 20 ₁, that is, to the transfer device30 ₃.

[0077] (Operation of the Communications System in Embodiment 1)

[0078] The operation of the communications system according to thisembodiment will be described with reference to FIGS. 5 and 6. FIG. 5 isa sequence diagram illustrating the operation of the communicationssystem of this embodiment.

[0079] As shown in FIG. 5, in step 401, the first terminal 52 transmitsdata (including a data transmission request) including the destinationaddress “second terminal ID (destination ID, ID-terminal 51),” thesource address “first terminal ID (source terminal ID, ID-terminal 52),”control information (e.g., communication speed=64 Kbps) and userinformation (such as a payload) to the first transfer device 30 ₁. Adata format for the transmission is shown in FIG. 6A.

[0080] Upon receiving the data transmission request, the receiver 21 ofthe first transfer device 30 ₁, searches the terminal ID-routinginformation-control information associating unit 24 for a recordincluding the “second terminal ID (ID-terminal 51)” as the “destinationterminal ID.”

[0081] When the terminal ID-routing information-control informationassociating unit 24 includes the record, the routing processor 25 adds,in step 405, to the data the “destination transfer device ID, that is,the routing information for routing the data to the second transferdevice 20 ₁, (ID RA-20 ₁ of the second transfer device 20 ₁)” associatedwith the “second terminal ID (ID-terminal 51),” and transfers the datato the transfer device 303 specified in the “transfer information”associated with the “second terminal ID (ID-terminal 51),” based on the“control information” associated with the “second terminal ID(ID-terminal 51)” (see FIG. 6B).

[0082] When the terminal ID-routing information-control informationassociating unit 24 does not include the record, the transfer requesttransmitter 22 transmits, in step 402, to the network manager 10 a“transfer request” including the “second terminal ID (ID-terminal 51)”and the “control information (communication speed=64 Kbps).”

[0083] In step 403, upon the transfer request received via the transferrequest receiver 11, the routing information setting instructing unit 14of the network manager 10 searches the terminal ID-location informationassociating unit 12 and the location information-transfer device IDassociating unit 13, with the “second terminal ID (ID-terminal 51)”included in the transfer request as a keyword.

[0084] The routing information setting instructing unit 14 obtains the“destination transfer device ID (ID RA-20 ₁ of the second transferdevice 20 ₁)” associated with the “second terminal ID (ID-terminal 51)”and transmits to the plurality of transfer devices 20 ₁, 20 ₃, 30 ₁, and30 ₃, a “routing information setting instruction (instructioninformation.)” including the “routing information for routing the datato the second transfer device 20 ₁, (ID RA-20 ₁, of the second transferdevice 20 ₁), ” the “transfer information (ID RA-30 ₃ of the transferdevice 30 ₃)” and the “control information (communication speed=64Kbps).”

[0085] In step 404, the routing information setting instruction receiver23 of each of the plurality of transfer devices 20 ₁, 20 ₃, 30 ₁ and 30₃ updates the memory contents of the terminal ID-routinginformation-control information associating unit 24 according to the“routing information setting instruction (instruction information)”received from the network manager 10. The routing information settinginstruction receiver 23 of the first transfer device 30 ₁, for example,updates the terminal ID-routing information-control informationassociating unit 24 according to the “routing information settinginstruction (instruction information)” as shown in FIG. 4.

[0086] In step 405, the routing processor 25 of the first transferdevice 30 ₁, adds to the data the “routing information for routing thedata to the second transfer device (ID RA-20 ₁)” associated with the“second terminal ID (ID-terminal 51)” included in the data transmittedvia the receiver 21 from the first terminal 52, and transfers the datavia the transmitter 26 to the transfer device 30 ₃ specified in the“transfer information” associated with the “second terminal ID(ID-terminal 51),” based on the “control information (communicationspeed=64 Kbps)” associated with the “second terminal ID (ID-terminal51).”

[0087] The data transmitted includes, as shown in FIG. 6B, the “routinginformation for routing the data to the second transfer device 20 ₁,(RA-20 ₁), “the destination address “second terminal ID (destinationterminal ID, ID-terminal 51),” the source address “first terminal ID(source terminal ID, ID-terminal 52)” and the “user information(payload).”

[0088] In step 406, the transfer device 303 transfers, in the samemanner as the first transfer device 30 ₁, the data received from thefirst transfer device 30 ₁, to the transfer device 20 ₃ connected to thesubnetwork 2. The data transmitted includes, as shown in FIG. 6B the“routing information for routing the data to the second transfer device20 ₁, (ID RA-20 ₁),” the destination address “second terminal ID(destination terminal ID, ID-terminal 51),” the source address “firstterminal ID (source terminal ID, ID-terminal 52)” and the “userinformation.” The data is transferred at the communication speed of 64Kbps based on the “control information (communication speed=64 Kbps).”

[0089] In step 407, the transfer device 20 ₃ transfers, in the samemanner as the first transfer device 30 ₁, the data received from thetransfer device 30 ₃ to the second transfer device 20 ₁. The datatransferred includes, as shown in FIG. 6B, the “routing information forrouting the data to the second transfer device 20 ₁, (RA-20 ₁),” thedestination address “second terminal ID (destination terminal ID,ID-terminal 51),” the source address “first terminal ID (source terminalID, ID-terminal 52)” and the “user information.” The data is transferredat the communication speed of 64 Kbps based on the “control information(communication speed=64 Kbps).”

[0090] In step 408, the second transfer device 20 ₁ deletes the “routinginformation for routing the data to the second transfer device 20 ₁.(RA-20 ₁)” from the data received from the transfer device 20 ₃ andtransmits the data to the second terminal 51. The data transferredincludes, as shown in FIG. 6A, the destination address “second terminalID (destination terminal ID, ID-terminal 51),” the source address “firstterminal ID (source terminal ID, ID-terminal 52)” and the “userinformation.”

[0091] In step 409, the second terminal 51 transmits data destinationaddress “first terminal ID (destination terminal ID, ID-terminal 52),”the source address “second terminal ID (source terminal ID, ID-terminal51),” the control information (communication speed=64 Kbps)” and the“user information,” to the second transfer device 20 ₁.

[0092] In step 410, the receiver 21 of the second transfer device 20 ₁,searches the terminal ID-routing information-control informationassociating unit 24 for a record including the “first terminal ID(destination terminal ID, ID-terminal 52)” as the “destination terminalID,” according to the data including the data transmission request.

[0093] When the terminal ID-routing information-control informationassociating unit 24 includes the record, the routing processor 25 of thesecond transfer device 20 ₁ adds, in step 410, to the data “routinginformation for routing the data to the first transfer device (RA-30 ₁)”associated with the “first terminal ID (destination terminal ID,ID-terminal 52),” and transfers the data via the transmitter 26 to thetransfer device 20 ₃ specified in the “transfer information” associatedwith the “first terminal ID (destination terminal ID, ID-terminal 52),”based on the “control information.”

[0094] The data transmitted includes, as shown in FIG. 6B, the “routinginformation for routing the data to the first transfer device 30 ₁ (IDRA-30 ₁),” the destination address “first terminal ID (destinationterminal ID, ID-terminal 52),” the source address “second terminal ID(source terminal ID, ID-terminal 51)” and the “user information.”

[0095] In step 411, the transfer device 20 ₃ transfers, in the samemanner as the second transfer device 20 ₁,the data received from thesecond transfer device 20 ₁ to the transfer device 30 ₃ connected to thesubnetwork 3. The data transferred includes, as shown in FIG. 6B, the“routing information for routing the data to the first transfer device30 ₁ (ID RA-30 ₁),” the destination address “first terminal ID(destination terminal ID, ID-terminal 52),” the source address “secondterminal ID (source terminal ID, ID-terminal 51)” and the “userinformation.” The data is transferred at the communication speed of 64Kbps based on the “control information (communication speed=64 Kbps).”

[0096] In step 412, the transfer device 30 ₃ transfers, in the samemanner as the second transfer device 20 ₁, the data received from thetransfer device 20 ₃ to the first transfer device 30 ₁. The datatransferred includes, as shown in FIG. 6B, the “routing information forrouting the data to the first transfer device 30 ₁ (ID RA-30 ₁),” thedestination address “first terminal ID (destination terminal ID,ID-terminal 52),” the source address “second terminal ID (sourceterminal ID, ID-terminal 51)” and the “user information.” The data istransferred at the communication speed of 64 Kbps based on the controlinformation (communication speed=64 Kbps).”

[0097] In step 413, the first transfer device 30 ₁ deletes the “routinginformation for routing the data to the first transfer device 30 ₁(RA-30 ₁)” from the data received from the transfer device 30 ₃ andtransmits the data to the first terminal 52. The data transferredincludes, as shown in FIG. 6A, the destination address “first terminalID (destination terminal ID, ID-terminal 52),” the source address“second terminal ID (source terminal ID. ID-terminal 51)” and the “userinformation.”

[0098] (Function/Effect of the Communications System in Embodiment 1)

[0099] According to the communications system of this embodiment, theterminal ID-routing information-control information associating unit 24of the first transfer device 30 ₁ stores the “the second terminal(destination terminal) ID (ID-terminal 51)” and the “routing informationfor routing the data to the second transfer device 20 ₁ (RA-20 ₁),”associating them with one another, and the routing processor 25 adds tothe data the “routing information for routing the data to the secondtransfer device 20 ₁ (RA-20 ₁) associated with the “second terminal ID(ID-terminal 51)” and transfers the data from the first terminal 52 tothe second terminal 51. This eliminates the need for going through arelay point (home agent) constituting a triangular path.

[0100] According to the communications system of this embodiment, thefirst terminal (source terminal) 52 only needs to transmit dataincluding the “second terminal ID(destination terminal) (ID-terminal51)” as the destination address. This eliminates the need forcomplicated settings at the first terminal 52.

[0101] The communications system of this embodiment further eliminatesthe need for holding, at the first terminal 52, both address informationassigned by the access network (subnetwork 3) and the home address ofthe first terminal 52, and performing the release of encapsulation orthe like of packets or the like received.

[0102] According to the communications system of this embodiment, thefirst terminal 52 does not need to transmit the “routing information forrouting the data to the second transfer device (RA-20 ₁)” to the accesspoint in the access network (first transfer device 30 ₁). Thiseliminates the need for transmitting and receiving packets in a formatincluding an information element as an overhead also in a radio sectionor the like between the first terminal 52 and the access point in theaccess network (first transfer device 30 ₁).

[0103] (Configuration of a Communications System in Embodiment 2)

[0104] The configuration of a communications system according to asecond embodiment of the present invention will be described mainly ondifference from the communications system according to the firstembodiment. The entire configuration of the communications system in thesecond embodiment of this invention is identical to that of thecommunications system of the first embodiment.

[0105] A network manager 10 includes, as shown in FIG. 7A, instead ofthe terminal ID-location information associating unit 12 and thelocation information-transfer device ID associating unit 13 in the firstembodiment, a third memory storing a “communication ID element,” a“source terminal ID (first terminal ID),” a “destination terminal ID(second terminal ID)” and a “destination transfer device ID (routinginformation for routing the data to a second transfer device),”associating them with one another.

[0106] A routing information setting instructing unit 14 of the networkmanager 10 constitutes an instruction information transmitter fortransmitting, upon a transfer request including the “first and secondterminal IDs” transmitted from a first transfer device 30 ₁, a “routinginformation setting instruction (instruction information)” including the“routing information for routing the data to the second transfer device(destination transfer device ID)” and the “communication ID element”associated with the “first and second terminal IDs.”

[0107] When a receiver 22 of the first transfer device 30 ₁ receives a“data transmission request” including the destination address “secondterminal ID,” the source address “first terminal ID” and “controlinformation (communication speed=64 Kbps),” the receiver 22 searches aterminal ID-routing information-control information associating unit 24for a record including the “first terminal ID” and the “second terminalID” included in the received “data transmission request.”

[0108] When the terminal ID-routing information-control informationassociating unit 24 includes the record, the receiver 21 transmits a“transmission setting response” including the “communication ID element”associated with the record, to the first terminal 52.

[0109] When the terminal ID-routing information-control informationassociating unit 24 does not include the record, the receiver 21transfers the “data transmission request” to a transfer requesttransmitter 22.

[0110] When receiving data including the “communication ID element” fromthe first terminal 52, the receiver 21 transfers the data to a routingprocessor 25.

[0111] The transfer request transmitter 22 transmits, upon the “datatransmission request” received through the receiver 21, a “transferrequest” including the “first terminal ID, ” the “second terminal ID”and “the control information” to the network manager 10.

[0112] In this embodiment, the receiver 21 and the transfer requesttransmitter 22 constitute a transfer request transmitter fortransmitting a “transfer request” to the network manager 10 whenreceiving a “data transmission request” from the first terminal 52.

[0113] A routing information setting instruction receiver 23 updates thememory contents of the terminal ID-routing information-controlinformation associating unit 24, according to a “routing informationsetting instruction (instructing information)” received from the networkmanager 10.

[0114] The terminal ID-routing information-control informationassociating unit 24 constitutes a first memory storing, as shown in FIG.7B, “communication ID elements,” “source terminal IDs (first terminalIDs),” “destination terminal IDs (second terminal IDs),” “destinationtransfer device IDs (routing information for routing the data to thesecond transfer devices),” “transfer information” and “controlinformation,” associating them with one another.

[0115]FIG. 7B illustrates an example of the memory contents of theterminal ID-routing information-control information associating unit 24.In the example of FIG. 7B, the terminal ID-routing information-controlinformation associating unit 24 stores a first record including a“communication ID element=71,” a “source terminal ID=ID-terminal 52,” a“destination terminal ID=ID-terminal 51, a “destination transferterminal ID=RA-20 ₁ (information identifying the second transfer device20 ₁,” “transfer information=RA-30 ₃” and “control information=64 Kbps,”and a second record including a “communication ID element=72,” a “sourceterminal ID=ID-terminal 51,” a “destination terminal ID=ID-terminal 52,”a “destination transfer terminal ID=RA-30 ₁ (information identifying thefirst transfer device 30 ₁,” “transfer information=Wireless” and“control information=none.”

[0116] The routing processor 25 adds to the data the “destinationtransfer device ID (routing information for routing the data to thesecond transfer device” associated with the “communication ID element”included in the data received through the receiver 21, and transfers thedata to the transfer device specified in the “transfer information”associated with the “communication ID element” based on the “controlinformation.”

[0117] (Operation of the Communications System in Embodiment 2)

[0118] The operation of the communications system according to thisembodiment will be described with reference to FIGS. 8 and 9. FIG. 8 isa sequence diagram illustrating the operation of the communicationssystem of this embodiment.

[0119] As shown in FIG. 8, in step 701, the first terminal 52 transmitsa “data transmission request” including the destination address “secondterminal ID (destination ID, ID-terminal 51),” the source address “firstterminal ID (source terminal ID, ID-terminal 52)” and controlinformation (e.g., communication speed=64 Kbps) to the first transferdevice 30 _(1.) A data format for the transmission is shown in FIG. 9A.

[0120] The receiver 21 of the first transfer device 30 ₁ searches, uponthe “data transmission request,” the terminal ID-routinginformation-control information associating unit 24 for a recordincluding the “second terminal ID (destination terminal ID, ID-terminal51)” and the “first terminal ID (source terminal ID, ID-terminal 52).”

[0121] When the terminal ID-routing information-control informationassociating unit 24 includes the record, the receiver 21 of the firsttransfer device 30 ₁ transmits, in step 705, in response to the “datatransmission request,” a “transmission setting response” including the“communication ID element” associated with the “second terminal ID(destination terminal ID, ID-terminal 51)” and the “first terminal ID(source terminal ID, ID-terminal 52)”, to the first terminal 52.

[0122] When the terminal ID-routing information-control informationassociating unit 24 does not include the record, the transfer requesttransmitter 22 of the first transfer device 30 ₁ transmits, in step 702,to the network manager 10 a “transfer request” including the “secondterminal ID (destination terminal ID, ID-terminal 51),” the “firstterminal ID (source terminal ID, ID-terminal 52)” and the “controlinformation

[0123] (Communication Speed=64 Kbps).”

[0124] In step 703, upon the transfer request received via the transferrequest receiver 11, the routing information setting instructing unit 14of the network manager 10 searches the third memory, with the “secondterminal ID (ID-terminal 51)” and the “first terminal ID (ID-terminal52)” included in the transfer request as keywords.

[0125] The routing information setting instructing unit 14 obtains the“communication ID element,” the “destination transfer device ID” and the“transfer information” associated with the “second terminal ID(ID-terminal 51)” and the “first terminal ID (ID-terminal 52),” andtransmits to a plurality of transfer devices 20 ₁, 20 ₃, 30 ₁ and 30 ₃,a “routing information setting instruction (instruction information)”including the “communication ID element (71),” the “destination transferdevice ID” and the “transfer information.”

[0126] In step 704, the routing information setting instruction receiver23 of each of the plurality of transfer devices 20 ₁, 20 ₃, 30 ₁ and 30₃ updates the memory contents of the terminal ID-routinginformation-control information associating unit 24 according to the“routing information setting instruction (instruction information)”received from the network manager 10. The routing information settinginstruction receiver 23 of the first transfer device 30 ₁, for example,updates the terminal ID-routing information-control informationassociating unit 24 according to the “routing information settinginstruction (instruction information)” as shown in FIG. 7B.

[0127] In step 705, the receiver 21 of the first transfer device 30 ₁transmits to the first terminal 52 a “transfer setting response”including the “communication ID element (71)” associated with the“second terminal ID (destination terminal ID, ID-terminal 51)” and the“first terminal ID (source terminal ID, ID-terminal 52).”

[0128] In step 706, the first terminal 52 transmits data including the“communication ID element (71).” The data transmitted includes, as shownin FIG. 9B, the “communication ID element (71)” and “user information.”

[0129] In step 707, the routing processor 25 of the first transferdevice 30 ₁ adds to the data the “destination transfer device ID(routing information for routing the data to the second transfer device,RA-20 ₁)” associated with the “communication ID element (71)” includedin the data transmitted via the receiver 21 from the first terminal 52,and transfers the data via the transmitter 26 to the transfer device 30₃ specified in the “transfer information” associated with the“communication ID element (71).”

[0130] The data transmitted includes, as shown in FIG. 9C, the“destination transfer device ID (routing information for routing thedata to the second transfer device 20 ₁, RA-20 ₁),” the communication IDelement (71)” and the “user information.” The data is transferred at thecommunication speed of 64 Kbps based on the “control information(communication speed=64 Kbps).”

[0131] In step 708, the transfer device 30 ₃ transfers, in the samemanner as the first transfer device 30 ₁, the data received from thefirst transfer device 30 ₁ to the transfer device 20 ₃ connected to asubnetwork 2. The data transferred includes, as shown in FIG. 9C, the“destination transfer device ID (routing information RA-20 ₁ of thesecond transfer device 20 ₁),” the communication ID element (71)” andthe “user information.” The data is transferred at the communicationspeed of 64 Kbps based on the “control information (communicationspeed=64 Kbps).”

[0132] In step 709, the transfer device 20 ₃ transfers, in the samemanner as the first transfer device 30 ₃, the data received from thetransfer device 30 ₃ to the second transfer device 20 ₁. The datatransferred includes, as shown in FIG. 9C, the “destination transferdevice ID (routing information RA-20 ₁ of the second transfer device 20₁),” the communication ID element (71)” and the “user information.” Thedata is transferred at the communication speed of 64 Kbps based on the“control information (communication speed=64 Kbps).”

[0133] In step 710, the second transfer device 20 ₁ deletes the“destination transfer device ID (routing information RA-20 ₁ of thesecond transfer device)” from the data received from the transfer device20 ₃ and transmits the data to the second terminal 51. The datatransmitted includes, as shown in FIG. 9B, the “communication ID element(71)” and the “user information.”

[0134] In step 711, the second terminal 51 transmits data including the“communication ID element (71).” The data transmitted includes, as shownin FIG. 9B, the “communication ID element (71)” and the “userinformation.”

[0135] In the following steps 712 to 715, the data is transmitted to thefirst terminal 51 in the same manner as in steps 707 to 710.

[0136] (Function/Effect of the Communications System in Embodiment 2)

[0137] According to the communications system of this embodiment, sincethe routing processor 25 adds to the data the routing informationassociated with the communication ID element included in the datareceived from the first terminal 52 and transfers the data to the secondtransfer device 20 ₁, the first terminal ID and the second terminal IDare not included in data transferred in the communications system,increasing the confidentiality of communications.

[0138] (Communications System in Embodiment 3)

[0139] A communications system according to a third embodiment of thepresent invention will be described mainly on difference from thecommunications system of the first embodiment.

[0140] The communications system according to this embodiment isdifferent from the communication system of the first embodiment in thata routing information setting instructing unit 14 of a network manager10 transmits a “routing information setting instruction (instructioninformation)” to a second transfer device 20 ₁ instead of transmittingto a plurality of transfer devices 20 ₁, 20 ₃, 30 ₁ and 30 ₃, and thesecond transfer device 20 ₁ transmits the “routing information settinginstruction (instruction information)” to the plurality of transferdevices 20 ₃, 30 ₁ and 30 ₃.

[0141] The operation of the communications system of this embodiment isidentical to the operation of the communications system of the firstembodiment except that in step 1003 in FIG. 10, the routing informationsetting instructing unit 14 of the network manager 10 transmits a“routing information setting instruction (instruction information)” tothe second transfer device 20 ₁, and in step 1005, the second transferdevice 20 ₁ transmits the “routing information setting instruction(instruction information)” to the plurality of transfer devices 20 ₃, 30₁ and 30 ₃.

[0142] Modification

[0143] In the communications systems of the above embodiments, theterminal ID-routing information-control information associating unit 24may store, as the “transfer information,” the type of radiocommunications with the first terminal 52 or the “port number” for usein the radio communications.

[0144] The communications systems of the above embodiments may use otherformats instead of those shown in FIGS. 6 and 9.

[0145] The communications systems of the above embodiments may use, asthe “control information,” data encryption information.

[0146] In the communications system of the above embodiment, at leastone of the “first terminal ID” and the “second terminal ID” may bechanged to a distinct independent ID in the network 1 or the subnetworks2 or 3.

[0147]FIGS. 11A and 11B illustrate an example of data formats for use inchanging to a distinct independent ID. FIG. 12 illustrates an example ofthe configuration of the terminal ID-routing information-controlinformation associating unit 24 at that time.

[0148] The routing processor 25 changes the “second terminal ID(destination terminal ID)” included in data received from the firstterminal 52 to the corresponding “network destination terminal ID,”adding to the data routing information for routing the data to the“destination transfer device ID (NWID-terminal 51)” associated with the“second terminal ID (destination terminal ID).”

[0149] As shown in FIG. 11B, the routing processor 25 may change the“first terminal ID (source terminal ID)” included in data received fromthe first terminal 52 to the corresponding “network destination terminalID.”

[0150] In the communications system of the above embodiment, the“communication TD element” may be changed to a distinct independent IDin the network 1 or subnetworks 2 or 3.

[0151] When a system in which the “transfer information” agrees with the“destination transfer device ID” in the memory contents of the terminalID-routing information-control information associating unit 24 in FIGS.4, 7 or 12 is used, the “transfer information” may be omitted.

[0152] When the network manager 10 manages “source terminal IDs” and“destination terminal IDs” associated with “communication ID elements,”“source terminal IDs” and “destination terminal IDs” may be omitted inthe memory contents of the terminal ID-routing information-controlinformation associating unit 24 in FIG. 7. When destination terminal IDsare not included, for example, communication ID elements may beassociated with routing information.

[0153] In the communication systems of the above embodiments, theprocessing performed in the first transfer device 30 ₁ may be performedin the other transfer device 20 ₁, 20 ₃ or 30 ₃.

[0154] (Effects of the Invention)

[0155] As described above, the present invention provides acommunications system and a communications method which allow transferof data not using a terminal ID assigned by an access network but usingrouting information distinct from the terminal ID, and a transfer deviceand a network manager suitable for use therein.

[0156] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and the representativeembodiment shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. A communications system for transmitting dataincluding, as a destination address, a second terminal ID, from a firstterminal to a second terminal via a plurality of transfer devices, thesystem comprising: a first transfer device connected to the firstterminal, the first transfer device comprising: a first memoryconfigured to store the second terminal ID and routing information forrouting the data to a second transfer device connected to the secondterminal, associating them with one another; and a routing processorconfigured to add to the data the routing information associated withthe second terminal ID included in the data received from the firstterminal, and to transfer the data to the second transfer device.
 2. Acommunications method of transmitting data including, as a destinationaddress, a second terminal ID, from a first terminal to a secondterminal via a plurality of transfer devices, the method comprising thestep of: A) adding to the data, at a first transfer device which isconnected to the first terminal and stores the second terminal ID androuting information for routing the data to a second transfer device towhich the second terminal is connected, associating them with oneanother, the routing information for routing the data to the secondtransfer device associated with the second terminal ID included in thedata, and transferring the data to the second transfer device.
 3. Afirst transfer device connected to a first terminal for transmittingdata including, as a destination address, a second terminal ID, from thefirst terminal to the second terminal, the first transfer devicecomprising: a first memory configured to store the second terminal IDand routing information for routing the data to a second transfer deviceto which the second terminal is connected, associating them with oneanother; and a routing processor configured to add to the data therouting information associated with the second terminal ID included inthe data, and to transfer the data to the second transfer device.
 4. Afirst transfer device as set forth in claim 3, further comprising: atransfer request transmitter configured to transmit a transfer requestincluding the second terminal ID to a network manager upon receiving atransmission request for the data from the first terminal; wherein, thefirst memory stores the second terminal ID and the routing informationfor routing the data to the second transfer device, associating themwith one another, upon receiving instruction information including therouting information associated with the second terminal ID from thenetwork manager.
 5. A first transfer device as set forth in claim 3,wherein: the first memory stores the second terminal ID, the routinginformation for routing the data to the second transfer device and acommunication ID element, associating them with one another; and therouting processor adds to the data the routing information associatedwith the communication ID element included in the data received from thefirst terminal, and transfers the data to the second transfer device. 6.A first transfer device as set forth in claim 5, further comprising: atransfer request transmitter configured to transmit a transfer requestincluding a first terminal ID and the second terminal ID to a networkmanager upon receiving a transmission request for the data from thefirst terminal; wherein, the first memory stores the first terminal ID,the second terminal ID, the routing information for routing the data tothe second transfer device and the communication ID element, associatingthem with one another, according to instruction information from thenetwork manager.
 7. A network manager for managing a communicationssystem for transmitting data including, as a destination address, asecond terminal ID, from a first terminal to the second terminal via aplurality of transfer devices, the network manager comprising: a secondmemory configured to store the second terminal ID and routinginformation for routing the data to a second transfer device to whichthe second terminal is connected, associating them with one another; andan instruction information transmitter configured to transmitinstruction information including the routing information associatedwith the second terminal ID, in response to a transfer request includingthe second terminal ID transmitted from a first transfer device to whichthe first terminal is connected.
 8. A network manager for managing acommunications system for transmitting data including a second terminalID as a destination address and including a first terminal ID as asource address, from the first terminal to the second terminal via aplurality of transfer devices, the network manager comprising: a thirdmemory configured to store the first terminal ID, the second terminalID, routing information for routing the data to a second transfer deviceto which the second terminal is connected and a communication IDelement, associating them with one another; and an instructioninformation transmitter configured to transmit instruction informationincluding the routing information for routing the data to the secondtransfer device to which the second terminal is connected and thecommunication ID element associated with the first terminal ID and thesecond terminal ID, in response to a transfer request including thefirst terminal ID and the second terminal ID transmitted from a firsttransfer device.